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Twopiece

P0420 - Catalyst System Efficiency below Threshold

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Hi All,

My car's engine light suddenly went "on", and i checked that the error code is P0420 - Catalyst System Efficiency below Threshold.

Went to a workshop and they told me cos I never speed my car long enough, carbon built up at the exhaust pipe area, nothing can be done with it.  So they just cleared the engine light with their device, and that's all.  Then after a few weeks, the engine light turned on again.

May I know any of you has such experience before?  According to the workshop i went to, they say such thing is very common in those eco cars.  Not sure if it's true?

Hope to hear some advices from gurus here.

Thank you!

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what car and how old and how many km?

 

likely your catalytic converter is dying or o2 sensor

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Posted (edited)

What car are you driving? Does it come with a petrol particulate filter?

Now that most cars have direct fuel injection the exhaust produces more particulates (much like a diesel engine). To pass emission standard a particulate filter is added.

Have you get an opinion from the AD workshop? Please go ask them. You go to some outside workshop they cant do anything cos they do not have the specific factory diagnostic tool. They cant reset the ecu and get reading from the exhaust side oxygen sensor to get the job done. Sometimes the error code does not show you the big picture. For your case it could be a leak along the exhaust system...anywhere from the exhaust manifold, gasket, exhaust pipe joint, oxygen sensor, etc etc. Need an experience mechanic to find out. I dunno where you go to and what exactly they have told you. Wtf is an "eco car"? Ppl come up with their own funny terms. What "dual injection"? it confuses ppl who are ignorant even more.

Edited by Watwheels

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Oh... my car is a 10 year old Honda Fit... 

wa... it sounds more complicated than what the workshop has told me...

haha... ya the workshop told me mine is one of those "eco cars" that is supposed to be more eco friendly? I'm not sure.. and they said in order to prevent such error, I probably need to drive up to 100-120 km/hr, and run for a few hours, which means shld drive up to Msia from time to time...

Indeed sounded a bit ridiculous... but then once the workshop saw the error code on their device, they confidently told me it's a very common problem... so... 

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16 minutes ago, Twopiece said:

Oh... my car is a 10 year old Honda Fit... 

wa... it sounds more complicated than what the workshop has told me...

haha... ya the workshop told me mine is one of those "eco cars" that is supposed to be more eco friendly? I'm not sure.. and they said in order to prevent such error, I probably need to drive up to 100-120 km/hr, and run for a few hours, which means shld drive up to Msia from time to time...

Indeed sounded a bit ridiculous... but then once the workshop saw the error code on their device, they confidently told me it's a very common problem... so... 

https://www.700r4transmissionhq.com/p0420-honda-fit/

Does not sound ridiculous as Cat needs heat to work properly.

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P0420 code means that yr cat convertor is chocked with carbon. The quick solution is to pump in detergent via the O2 sensor opening and allow the cleaning agent to soak up the carbon. The next action is to start and rev up the engine to above 2500 rpm.

U3C.jpg

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Edited by Yeobh
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